The goal of the study of Pediatric Heart Transplantation at Stanford is to learn about the growth and neurodevelopment of children who had cardiovascular surgery prior to their second birthday. Those infants who received a heart transplant are compared with infants who underwent other major heart surgery prior to two years of age. It was the purpose of this investigation to assess these infants on an outpatient basis in the Mary L. Johnson Infant Development Clinic to evaluate growth and development, speech and language, and psychological development. Hearing assessments were made at the California Ear Institute. All of the 18 surviving heart transplant subjects were contacted and assessed to some degree. One male subject is autistic so very little data was obtained on this subject. One female subject lived out of state and only language assessment was obtained on this subject. It was possible to match 16 heart surgery subjects who met the criteria of age and sex and who were willing and able to return to the follow-up clinic for the necessary battery of tests.